ICM - Nutrition Flashcards
Which patients may need nutritional support?
- Malnourished patients:
- BMI <18.5
- Unintentional weight loss of >10% in last 3-6 months
- BMI <20 and unintentional weight loss of >5% in last 3-6 months - Risk of malnutrition
- Eaten nothing for last 5 days/expected to eat nothing for 5 days or more
- Poor absorptive capacity or high nutritional losses
- High catabolic state
Which patients are at risk of refeeding syndrome?
- One or more of:- BMI <16- Unintentional weight loss >15% in last 3-6 months- No nutritional intake for 10 days- Low levels of potassium, phosphate or magnesium2. Two or more of:- BMI <18.5- Unintentional weight loss >10% in last 3-6 months- No nutrition for >5 days- History of alcohol abuse or medications (e.g. insulin, chemo, antacids, diuretics).Reintroduction of nutritional requirements should be done in consultation with dietician and nutritional team.- consider reintroducing at 30% of normal energy and protein requirements - build up slowly over 7 days.- Ensure adequate B vitamin replacement (Pabrinex one daily/oral B vitamins, thiamine and multivitamins) for 10 days.- Monitor and replace potassium, phosphate and magnesium.
What are the basic daily nutritional requirements for an adult?
Energy: 25-35kcal/kg/day
Protein: 0.8-1.5g/kg/day
Nitrogen: 0.13-0.24g/kg/day
Fluid: 30-35ml/kg/day
Electrolytes:
- Na 1mmol/kg/day
- K 1mmol/kg/day
- Cl 1-2mmol/kg/day
- Mg 0.1mmol/kg/day
- Ca 0.1 mmol/kg/day
- PO 0.4 mmol/kg/day
- Vitamins, minerals and micronutrients```
When should reduced nutritional support be considered?
In:
- Critically ill patients
- - Patient without nutrition for 5 days
- Energy and protein requirements should be introduced at 50% for first 48hrs and then slowly increased.Electrolyte, fluids, vitamins and minerals should be met at 100%
How can you assess a patient’s nutritional state?
- Clinical assessment2. BMI3. Laboratory studies
How can you assess a patient’s nutritional requirements?
- Indirect calorimetry2. Equations (Schofield) - become less accurate the more critically unwell3. Weight-based
How can you assess a patient’s nutritional state?
- Clinical assessment - recent weight loss, severity of illness, GI dysfunction, MUST scoring.
- Anthropometric assessments - BMI, MUAC.
- Laboratory markers
How can you assess a patient’s nutritional requirements?
- Indirect calorimetry
- Nutritional index equations (Schofield, Harris-Benedict) - become less accurate the more critically unwell
- Weight-based/IBW
Is there an increased mortality risk associated with parenteral nutrition?
Parenteral nutrition does not increase mortality at 30 days (CALORIES)
Early parenteral nutrition not found to improve outcome (EPaNIC)
What is refeeding syndrome?
A constellation of features resulting from the rapid reinstitution of feeding/carbohydrate in patient’s who have been food/calorie deprived.
The reinstitution of carbohydrate and feed results in a surge in insulin release with a rapid intracellular shift of K, PO4, Mg.
Clinical features include:
- severe muscle weakness
- respiratory failure
- cardiac arrhythmias
- hypotension
- coma
What is the respiratory quotient?
RQ = CO2 produced / O2 consumed
If metabolism consists solely of lipids, the respiratory quotient is approximately 0.7, for proteins it is approximately 0.8, and for carbohydrates it is 1.0
What is the MUST Score?
‘MUST’ is a five-step screening tool to identify adults, who are malnourished, at risk of malnutrition
(undernutrition), or obese
Step 1
Measure height and weight to get a BMI score using chart provided. If unable to obtain
height and weight, use the alternative procedures shown in this guide.
Step 2
Note percentage unplanned weight loss and score using tables provided.
Step 3
Establish acute disease effect and score.
Step 4
Add scores from steps 1, 2 and 3 together to obtain overall risk of malnutrition.
Step 5
Use management guidelines and/or local policy to develop care plan.
What are proteins?
Proteins are macromolecules that comprise one or more long chains of amino acid
Protein synthesis occurs in all cells of the body via transcription and then translation.
Protein breakdown also occurs in all cells of the body catalysed by various enzymes, which include proteases.
What proteins are made in the liver?
Protein synthesis is stimulated by insulin and growth hormone. Some of the most important plasma proteins are synthesised in the liver.
Plasma proteins
Albumin
Globulin
Fibrinogen
CRP (an infection marker)
Clotting factors – Factors II, VII, IX and X are Vitamin K dependent
Thrombopoietin
Angiotensinogen
How are proteins catabolised?
This is done through the processes of transamination and deamination, before the ammonia generated is cleared in the urea cycle.
Through transamination, amino acids are converted into keto acids. The end result of this step is the generation of glutamate.
Deamination - Glutamate is metabolised further by glutamate dehydrogenase. The amine group is removed and rapidly forms ammonia (NH3) and subsequently ammonium (NH4+), alongside a-ketoglutarate. The ammonium is highly toxic and must therefore be removed through the urea cycle
The urea cycle occurs both within the mitochondria and cytoplasm of the hepatocyte. Through this process, the toxic ammonia is converted into harmless urea, which is easily excreted.
